The present invention is a method for manufacturing a siloxane compound described by formula R.sup.1.sub.m Si{OSi(CH.sub.3).sub.2 H}.sub.(4-m) comprising reacting a silane compound or condensation product of a silane compound described by formula R.sup.1.sub.m Si(OR.sup.2).sub.(4-m), where R.sup.1 is selected from the group consisting of hydrogen and substituted or unsubstituted monovalent hydrocarbon groups, R.sup.2 is selected from the group consisting of hydrogen, alkyl groups and alkoxyalkyl groups, and m is an integer from 0 to 3, with 1,1,3,3-tetramethyldisiloxane in an aqueous solution of an acid in which the acid concentration is 1.0 wt % or less, and the molar ratio of aqueous solution to the 1,1,3,3-tetramethyldisiloxane is in the range of 0.5 to 1.5. The method is particularly useful for manufacturing siloxane compounds having dimethylhydridosiloxy groups.
Japanese Patent Application Kokai No. 61-195129 and Japanese Patent Application Kokai No. 63-305133 propose methods for manufacturing siloxane compounds containing dimethylhydridosiloxy groups that can be described by general formula R.sup.1.sub.m Si{OSi(CH.sub.3).sub.2 H}.sub.(4-m), where R.sup.1 is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, and m is an integer from 0 to 3. However, large amounts of water and hydrochloric acid must be used. Accordingly, the efficiency is extremely poor, thus these methods are not suited to mass production. Furthermore, since a high concentration of hydrochloric acid is used, the siloxane compounds which are the desired products undergo a dehydrogenation type condensation reaction with 1,1,3,3-tetramethyldisiloxane.
The object of the present invention is to provide a method for the efficient selective manufacture of siloxane compounds which have dimethylhydridosiloxy groups.